Centrifuges are commonly used in operations involving operations such as the separation of a liquid and a solid of different densities, purifying a liquid, classifying various solids suspended in a liquid, dehydrating a solid, etc.
Centrifuges generally comprise a chamber, known as the bowl, into which the solid/liquid mixture is introduced, and an endless screw extending into the bowl along its axis. The bowl and the screw are driven in rotation at different speeds in order to carry out the abovementioned operations.
In conventional centrifuges, the bowl can be driven in rotation by an asynchronous electric motor via a belt, the screw being driven using a second motor coupled to a speed reducer. The two motors are generally frequency coupled by various well-known means.
However, in such centrifuges, the presence of a belt leads to vibration and slippage at the contacts between the belt and the drive shafts, whereas the bulk of such systems in terms of their volume and weight may prove prohibitive. Asynchronous electric motors are also subject to frequency slip which results in diminished performance.
It is also preferable in certain applications to use long-length small-diameter centrifuges. A disadvantage of such structures is the bending effect that may occur upon use of the device. This bending effect is particularly accentuated by the rotational speed and by the presence of belts between the driving spindles and the driven spindles, these belts exerting on the rotational spindles, a force perpendicular to them. The belts are therefore an obstacle stands in the way of increasing the rotational speed of such centrifuges because such increases lead to correspondingly increased bending.